EI Commander Timing Divergence Alarm
I recently had several Alarms on my dual Pmag setup using the EI Commander. I talked to Brad at Pmag about the problem and also Bill at EI Commander. As a result of those conversations I chose to take the situation seriously.
I pulled both Pmags and verified I had the hardened gears with official part numbers on them. The gears were in great shape.
As I was putting it all back together and setting the timing again, I believe I found the cause of the alarms. One of the vacuum lines going to one of the Pmags had a tiny slit in it. Just enough to leak sometimes. The slit happened right at the end of the little metal tube it connected to so pushing on it too hard with my arm when working in there could have caused it.
Since repairing it I have made to cross country flights of about 5 hours duration each with no alarms, and the divergence between them usually sits at 2 degrees.
In this case, the cause of the alarms did not cause any real danger, as one mag was simply not getting the signal to advance timing as much as the other one. It was a rather difficult item to trouble shoot and even after calling the experts, the cause was not on the "suspect list". That is why I write this here. If you get timing divergence alarms, check the vac lines, a mush easier task than checking the condition of the gears etc.
I recently had several Alarms on my dual Pmag setup using the EI Commander. I talked to Brad at Pmag about the problem and also Bill at EI Commander. As a result of those conversations I chose to take the situation seriously.
I pulled both Pmags and verified I had the hardened gears with official part numbers on them. The gears were in great shape.
As I was putting it all back together and setting the timing again, I believe I found the cause of the alarms. One of the vacuum lines going to one of the Pmags had a tiny slit in it. Just enough to leak sometimes. The slit happened right at the end of the little metal tube it connected to so pushing on it too hard with my arm when working in there could have caused it.
Since repairing it I have made to cross country flights of about 5 hours duration each with no alarms, and the divergence between them usually sits at 2 degrees.
In this case, the cause of the alarms did not cause any real danger, as one mag was simply not getting the signal to advance timing as much as the other one. It was a rather difficult item to trouble shoot and even after calling the experts, the cause was not on the "suspect list". That is why I write this here. If you get timing divergence alarms, check the vac lines, a mush easier task than checking the condition of the gears etc.